This uses the Fingerprint type more consistenly when handling
fingerprits rather then have various string representations passed
around and sometimes converted back and forth with slight differences
in strictness.
It fixes an important bug in the existing, but until now unused,
parsing behaviour of Fingerprint. It also adds a default length check
on the fingerprint as that was checked in some existing places.
Fially generating keys is no longer expensive, so let's not ignore
these tests.
the advanced options are not used anyway later,
but prevent imap/smtp connections from being altered.
nb: we want to stop altering when some advanced options
are entered, however, we want to do this probaby
not depending on autoconfig.
Fix#1474 "Sending message to contact with < or > in Recipient gets treated as "Sent" but is not received".
As I was at it, I also extracted the correct name and address from addresses like Mueller, Dave <dave@domain.com>.
This means all key conversions/serialisation/deserialisation can be
done with DcKey rather than Key. Also migrate all key conversion
tests to DcKey rather than Key.
This moves both the Keyring and the fingerprints to the DcKey trait,
unfortunately I was not able to disentangle these two changes. The
Keyring now ensures only the right kind of key is added to it.
The keyring now uses the DcKey::load_self method rather than
re-implement the SQL to load keys from the database. This vastly
simpliefies the use and fixes an error where a failed key load or
unconfigured would result in the message being treated as plain text
and benefits from the in-line key generation path.
For the fingerprint a new type representing it is introduced. The aim
is to replace more fingerpring uses with this type as now there are
various string representations being passed around and converted
between. The Display trait is used for the space-separated and
multiline format, which is perhaps not the most obvious but seems
right together with FromStr etc.
